Concentration dependent mobility of two-dimensional electron gas in GaAs/AlGaAs heterostructure

Abstract
High-pressure freezeout of electrons onto metastable states of a Si donor, as well as the persistent photoconductivity method were used to tune the concentration of a two-dimensional electron gas n2DEG in a GaAs/AlGaAs heterostructure. This made the measurement of the temperature dependence of the 2DEG mobility possible in a wide range of n2DEG values, even though this was applied to only one sample. Consequently, it enabled the determination of various contributions to 2DEG mobility and in particular the separation of the acoustic phonon scattering from other scattering mechanisms. The above procedure leads to the determination of the deformation potential and points out its screening by free carriers. This screening is well described by the random phase approximation. The resulting conduction band deformation potential was found to be 12.5+or-0.05 eV.